During fabrication of semiconductor devices on a semiconductor wafer, chemical mechanical polishing can be performed to smooth surfaces of the semiconductor wafer using chemicals and/or mechanical forces. For example, the semiconductor wafer can be polished to prepare the semiconductor wafer for a new layer of material. In one example of polishing, the semiconductor wafer can be secured to a polishing head configured to hold and rotate the semiconductor wafer (e.g., vacuum pressure can be used to secure the semiconductor wafer to the polishing head). The polishing head can apply force to the semiconductor wafer toward a polishing pad during polishing. The polishing head can rotate the semiconductor wafer against the polishing pad, which can also be rotating, to apply mechanical force to the semiconductor wafer to remove material and/or even out irregular topography of the semiconductor wafer, for example. In one example, chemicals, such as slurry (e.g., colloid), can be applied to the polishing pad during polishing to serve as solvents which aid in reducing non-uniformities on the surface of the semiconductor wafer.